Mechanical telephone



(No Model.)

H. M. OHAMBLI-N. MECHANICAL TELEPHONE.

No. 439,475. Patented Oct. 28, 1890.

UNITED STATES PATENT OFFICE.

HEMBURN M. OHAMBLIN, OF NEWTON, ILLINOIS.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent N 0. 439,475, dated October 28, 1890.

Application filed May 10, 1890. Serial No. 351,295. (No model.)

The object of the invention is to so improve the button connecting the lin e-wire to the diaphragm that the transmitted sounds will be reproduced more clearly and distinctly, as will more fully hereinafter appear.

In the drawings, A designates an ordinary mechanical or acoustic telephone provided withthe diaphragmB and mounted in anysuitable manner. The line-wire 0 passes through apertures in the back of the telephone-casing and diaphragm, and is connected to a concavoconvex button D,which it clamps to the center of the front face of the diaphragm. The

concave or hollow side of this button is toward the diaphragm, and its circular edge presses upon the face of the same. This button is provided with a suitable number ofsay three openings a,which connect the chamber formed between the hollowed-out side of the button and the diaphragm with the outside atmosphere.

Heretofore these hollow buttons have been imperforated, so as to form a dead-air space between them and the diaphragm, thereby giving to the sound reproduced a mufiled effect. It isa fact, demonstrated by experiment and use, that by perforating the button and allowing the air free access to the space behind it all muffiing and retardation of the reproductions will be avoided and a clear distinct enunciation produced. \Vhether my theory be correct or not, experiment has demonstrated the fact that the Open button insures a much more efficient operation and clearer enunciation, and counteracts the effect of the wind upon the line-wires more efiectually than the solid imperforated button.

Having thus fully described my invention, what I claim is The combination,in a mechanical telephone, of the casing and diaphragm, the liue-wi re, and a concave button secured to the end of the wire and having its concave side toward the diaphragm,'the said button being provided with one or more openings, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

I-IEMBURN M. CHAMBLIN.

Witnesses:

DAVID TR-EXLER, WILLIAM SUTTON. 

